qmk_firmware/tmk_core/common/arm_atsam/bootloader.c

/* Copyright 2017 Fred Sundvik
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "bootloader.h"
#include "samd51j18a.h"
#include "md_bootloader.h"

//Set watchdog timer to reset. Directs the bootloader to stay in programming mode.
void bootloader_jump(void) {
#ifdef KEYBOARD_massdrop_ctrl
    //CTRL keyboards released with bootloader version below must use RAM method. Otherwise use WDT method.
    uint8_t ver_ram_method[] = "v2.18Jun 22 2018 17:28:08";     //The version to match (NULL terminated by compiler)
    uint8_t *ver_check = ver_ram_method;                        //Pointer to version match string for traversal
    uint8_t *ver_rom = (uint8_t *)0x21A0;                       //Pointer to address in ROM where this specific bootloader version would exist

    while (*ver_check && *ver_rom == *ver_check) {              //While there are check version characters to match and bootloader's version matches check's version
        ver_check++;                                            //Move check version pointer to next character
        ver_rom++;                                              //Move ROM version pointer to next character
    }

    if (!*ver_check) {                                          //If check version pointer is NULL, all characters have matched
        *MAGIC_ADDR = BOOTLOADER_MAGIC;                         //Set magic number into RAM
        NVIC_SystemReset();                                     //Perform system reset
        while (1) {}                                            //Won't get here
    }
#endif

    WDT->CTRLA.bit.ENABLE = 0;
    while (WDT->SYNCBUSY.bit.ENABLE) {}
    while (WDT->CTRLA.bit.ENABLE) {}
    WDT->CONFIG.bit.WINDOW = 0;
    WDT->CONFIG.bit.PER = 0;
    WDT->EWCTRL.bit.EWOFFSET = 0;
    WDT->CTRLA.bit.ENABLE = 1;
    while (WDT->SYNCBUSY.bit.ENABLE) {}
    while (!WDT->CTRLA.bit.ENABLE) {}
    while (1) {} //Wait on timeout
}